Combination with smoke-tube boiler



Jan. 8, 1929..

M. TRESCHOW COMBINATION WITH SMOKE TUBE BOILER Filed Sept. 28, 1926 NVE NTOR.

BYEL QWFBM RTTORNETS.

Patented Jan. 8, 1929.

warren are res COMBINATION :WITI-I SMOKE-TUBE BOILER Appl ioataion filed September 28, 1926, Serial No. 1 538,353 and i Denmark Noveniber 21, 1925. 7

It is a well known arrangement in smoketube boilers that the gases after having passed through the first row or the first rows of smoke tubes are reversedin a return cham- 5 her located, wholly or partly, outside the t water space of the boiler, and from the said chamber pass. into the nextsmoke passage, or in the case of a boiler having tubes through which the gases only pass in one direction,

7 10 that the gases are carried to a smoke box 10- cated, wholly or partly, outside the water space of the boiler, and from the saidsmoke box areconduct/ed to the chimney through a smoke pipe or smoke flue, said return chamber or smoke box being removable for the purpose of givingaccess to the boiler tubes for cleaning the same.

On account of the. high temperature of their exterior surfaces such return chambers or smoke boxes, particularly the former, Will always cause a greatloss of heat and an inconvenient temperaturein the boiler room. The usual remedy against these drawbacks is the appliance of some non-conducting material. But an effective covering has been made diflicult by the high temperature prevailing, and the result obtained is sonegligible that such coating very often is wholly abandoned.

The object of the invention is to reduce substantially the loss of heat from the said return chambers or smoke boxes of tubular boilers by transmitting the waste heat given ofl by the return chambersand smoke boxes to the combustion air, either the secondary or the primary air, or to both. In this manner the air will become intensively heated, thus furthering an efiective combustion of the gases developed in the fire, which is of special 40 importance when the fire is burning low, as

' in such case thesecondary air, if not properly heated, will cause such a drop inthe temperature inthe combustion chamber as to render impossible a complete combustion of the gases,especially when bituminous fuel is used.

, Through the heattradiated from the return chamber or smoke boxof a boiler the combustion air maybe heated to 'a far higher degree than if heated by flowing through pasondary air.

sages which are wholly or partlyin contact with the boiler water, and the manner of heating the combustion air, as embodied in the present lnvention, is far more efficient'than in the cases wherethe heating is effected by conducting the combustion air, in some well known manner, through passages in the brickwork arranged in orabove the combus tion chamber, as the temperature in thejlat ter by this arrangementis reduced to, such an extent as to'minimize the: advantages gained by heating the combustion air. I

The transmission of waste heat to the combustion air from the returnchamber or smoke box of the-boiler is effected by providing air jackets surrounding the said return chambers or smoke boxes in such a manner as to estab-' lish hollow spaces-between the latter and the air jacket, and the combustion air is carried through these hollow spaces, either bymeans of the draft in the chimney or by forced draft. j For this purpose the hollow spaces communicate through one or several, apertures with the boiler room and also with -the combustion chamber of the boiler by a'pipe or passage for discharging the warm, see- In order to compel the 'combustion airto flow across the total heating surface of thereturn chamber the hollow space may be divided into passages by means of ribs directing the course of the air.

If the walls of the return chamber or smoke box have not been properly cooled down by the passage of the secondary air and consequently still possess asurplus of ,4

heat available for heating purposes the said 5 1 discharge pipe or passage may be continued down to the space below the grate of the boiler, thus making it possible to supply warm, primary air to the fireplace.

this purpose a special discharge ,pipe may also be arranged. The drawing shows an example of how the invention may be applied, both in a smoke-tube boiler with exterior return chamber, andin a smoke-tubeb'oiler' with'snioke V Fig'sfl and'21shoWtwo vertical"section's of a vertical smoke-tube boile'rwith exterior For 45, Y m niee ing ith th omb t o c am e y return chamber, at right angles to each other,

Fig. 3 a section following the line AB shell of the boiler, c-the fire door, 0? the grate.

e the smoke tubes communicating with the combustion chamber and with the removable 7 return chamber 1), f the smoke tubes communica-ting with the return chamber and ith he mehe e embe i 9 a par t wal wee he the spac a h mo ham er: h is the Wa th r urn t ember 21,? an outerwall spaced from the wall t an o mi g re i h. an. i ie ke l s g h re h ham 1, and h Pipe, see 2, establishing communication between the return chamberv a; formed the airjacket iand the combustion chamber of the boiler, and, it so desired, also. with the space below the grate. A tight fit between the. r m va r turn. hamb r e d t e p plate of the boiler obtainedin some well known: manner, for instance through a sand leek-m. F r i t ng t e retu n cha mehe 2; when the. h l r' he are to h el he an eye b t 1? be fi d on the f rmer a ap d o he engag d by the. hook e t cl ey te elling en. a ra s pe ded rom he, e l g ot her hee mak n i easy to rela ive the r tu n, ehemh T enn e ieh b tw en he. Pipe and e. a r ieeket sh d be a ily eta a l and ay; ne ae ,heef ee ed by a sa d leek at t upp r end 5 t e Pipe Z, int Wh e the end of an elbow not the air jacket engages. F -em't Pip Z'tjhe Wa s ec n a y air y be carried'to the combustion chamber a of he. fire pate, thr ug a pipe r passage u situated in the smoke chamber 9", and come 'ere pip s .0-

1 Instead of connecting the pipe Z- both with th ee chh tie c amber a at h b e end wit he space. b low the s ate as h wn in Fi 2, the pipe Zj may open only into one of h? name ep eee- In th r ease, a e y, when he P Z opens both into the combustion chamber a of the boiler and into the space below the grate cl, or when the pipe opens only into the combustion chamber or only into. the space below-the grate, dampers be provided as shownin Fig. 2 for regulating the airflowing through the passage or pipe Z.

The ribs o,'fsee Figs. 1 and t, are located in the air jacket 2', and because of these ribs the co nbnstion air is compelled to flow across the total heating surface of the return chamber. The apertures admit the cold air into the air jacket 71.

As the temperature in the return chamber of a smoke-tube boiler, see Fig. 1, is very high due to the fact that the gases in this case have only passed part or the heating surface, the combustion air will become intensively heated on its passage through the hollow space between the return chamber a d the iaeh t:

In smoketube, boilers which are not provided with return chamber and in which the gases are carried direct to a smoke box, as shown in Fig. 5, and consequently. have travelled along the total heating surface of the, boiler before entering the smoke box, the

temperature in the latter will be compara tively low and the combustion air correspondingly less heated. Still, the amount of heat given offin this manner will be so large that the smoke box would cause a consider able loss of heat, it not prevented by the said combination. e v

In Fig, 5 s is the smoke box, the other letters corresponding with those indicated in Figs. 1 and 2. The smoke pipe 00 is connected with the removable smoke box in some well known manner, making it easy to disconnect the latter andthe smoke pipe invention, what Having thus described I claim is 1. The combination with a smoke-tube boiler having uptake tubes and downtake tubes, of a removable member formin a rereturn chamber disposed outside of the boiler, and in communication with all of said tubes for receiving combustion gases from the uptake tubes and delivering said gases to the downtake tubes, the wallof said return chamber being enclosed by an air jacket communieating with the atmosphere through at least one aperture, and a pipe in communication with said air jacket and the fire box of the boiler thereby to utilize the waste heat of the return chamber for pre-heating the combustion air. I

2. The combination with a smoke-tube boiler having uptake tubes and down-take tub.es, of a removable member forming a return chamber disposed outside of the boiler, and in communication with all of said tubesi'or receiving combustion gases from the uptake tubes and delivering-said gases to the downtake tubes, the, wall of said return chamber being enclosed by an air jacket communicating with the atmosphere through at least one aperture, and a pipe in communication with said air jacket and the fire box of the boiler thereby to utilize the waste heat of the re-' cause the incoming air to contact with practically the entire surface of the wall of the return chamber.

3. The combination with a smoke-tube boiler having uptake tubes and downtake 5 tubes, of a removable member forming a return chamber disposed outside of the boiler, and in communication with all of said tubes for receiving combustion gases from the uptake tubes and delivering said gases to the 10 downtake tubes, the wall of said return cham her being enclosed by an air jacket communieating with the atmosphere through at least one aperture, a pipe in communication with said a1r acket and wlth the combustion chamber of the boiler and having a branch in communication with the space below the grate, and dampers'for controlling the passage of air through said pipe and branch.

In testimony whereof I have signed my f name to this specification.

MICHAEL TREscHoW; 

